Coupling nonterminal allytlc



Patented "Oct. 6, 1953 COUPLING NONTE RMI'NAL ALLYLIC HALIDE S.

Irv n D.v Webb, Wilmin E. I. du. Pont de Nemo gton, DeL, assig nor to. urs and Company, Wilmington, Del., a. corporation of Delaware NoDrawing. Application March 25,. 1950, Serial No. 151,985;

12 Claims. (01. 260-615) This invention relates to a process for coupling non-terminal organic allylic halides! It. also relates to a process for preparing unsaturated dialkoxy compounds by reacting ethers, containing non-terminal allylic halogen, with nickel carbonyl. This invention relates more particularly toa process for the. preparation of 1,10-dimethoxy-decadiene3,7.

It was known heretofore that. certain allylic halides react with nickel carbonyl to form nickel halides and diallylic compounds. (BelgianPatent 448,884; Chem. Abstracts 41:65:76.). It was not known heretofore, however, that allylic halides in which allylic halogen is not terminal could be coupled in this manner by the action of nickel carbonyl to give productsrcoupled predominantly in the terminal positions rather than through the carbons initially carrying the halogen. Furthermore, this coupling reaction has not been employed heretofore, inthe. preparation of dimethoxydecadiene from the methoxychloropentenes which are formed by reaction between chloromethyl ether and butadi'ene.

An object of this invention is to produce long chain compounds from relatively shorter chain allylic compounds. Another object is to prepare a long chain aliphatic ether having alkoxy groups in the terminal positions. A more specific object of theinvention is to prepare Lid-dimethoxydecadiene-3f7. Other objects of; the invention will appear hereinafter.

It has been discovered in accordance with this invention that non-terminal allylic halides are converted by the actionoi nickelcarbonyl to products which are formed by coupling of ter minal carbon atoms of the allylic halide rather than by coupling of the carbonatoms which were initially attached to the allylic halogen.

It has been discoyered ior example, that 1,10- dialkoxydecadienes-3,7 can be prepared very read ily by subjecting 3-chloro-5-alkoxypenten-1' to the action of nickel carbonyl. This reaction takes place at ordinary temperaturesand pressures. If desired, an inert solvent (e. g. water or an inert organic diluent, or a mixture of) such diluents) may be used. The nature of the inert organic diluent is not at all critical, suitable diluents' being aromatic hydrocarbons, aliphatic hydrocarbons, dialkyl ethers, alkanols, alkanoic acids, esters, and the like. A convenientsolvent: which may be used effectively in the practice of the invention is methanol,"

Suitable non-terminal allylic halides which may be employed in the practiceof the invention include B-chIoro-I-butene, 3,6-dichloro-rethQxyl-hexene, 3-chloro-l-pentene, etc.

nickel chloride.

The reaction whereby the coupling of. these halides occurs maybe illustrated as follows: zomoomomon=onomoi 1-chloro-5-methoxypenten-2.

i. Ni(C 201130 CH2CH2CHC1GH=CH' 3-chloro-5-methoxyp enten-l In practicing the invention itls. generally preferred to employ a temperature within the range of 0 C. to 150 C,..,..excellent results being. obtained at temperatures. within. the rangeofi 10 C. to 75 C.

One mol of, nickel carbonyl is. consumed; and one mol of nickel halide. is produced for each mol of dimethoxydecadiene formed. in the process above illustrated; It isgenerally highly desirable to, employ substantial quantities, of," nickel carbonyl, preferably at 1east.about0;5 molofjnickel carbonyl per mol of the, halide. reactant.

The inventionisillustratedf further by means of'the following example.

Example 1.-Intoa mixture containing 200 cc. butadiene, 1 gram hydroquinone and 5 grams anhydrous zinc chlorideat 10." C. was introduced 190. grams of chloromethyl ether with stirring after which the stirring was. continued for four hours. The resultingmixture was permitted to remain overnightin asealed container at a temperature of 5 C The mixture was then poured on ice, and the organiclayerwasseparated. This was washed with waterand dried by means of anhydrous potassium carbonate. Distillation oi the resulting mixture gave about ..l00,cc., of '3- chloro-5-methoxypentenr-l, B.. B. -6.2? CL/39 mm. and about cc. of 1-chloro-51-methoxy penten-2, B. P. 81-83 C./35"mm. onehundred fifteen grams of the 3rchloroe5-methoxypenten-1 isomer in 200. cc. methanol was'maintained. under nitrogen pressure while a: solution of cc. nickel carbonyl and 400cc. methanol was introduced. Themixture was maintained atatemperature of about 50-60 overnight in a reaction flask which was equippedwitharefluxcondenser. The next day themethanolwas distilledfrom the mixture at atmospheric pressure; and the residue was extracted with lowmolecularweight mixed alkanes to separate the-organic material'from The organic extractwas then washed with water toremove the traces of nickel chloride which remained. Upon evaporation of the solvent and distillation of the residue under diminished pressure, a fraction consisting predominantly of 1,10-dimethoxydecadiene-3,7, B. P. 138-142 C./25 mm., was obtained (weight 69 grams, N 1.4505). The infra-red absorption curve for this material showed that it did not contain appreciable terminal unsaturation. The 1-chloro-5-1nethoxypenten-2 isomer was treated in the same manner and gave the same 1,10- dimethoxydecadiene-3,7 (B. P. 120-125 C./14 mm., N 14492-14500) in excellent yield, and the infra-red absorption spectrum was identical to that obtained above.

Example 2.--3-chloro-1-butene, B. P. 63, Na i? 1.4143 (after separation from its isomer, crotyl chloride, both of which were prepared by addition of hydrogen chloride to butadiene) was heated for several hours with a slight excess of nickel carbonyl at about 50 C., and the product was distilled. From 330 grams of 3-chloro-1- butene, the yield of octadienes was 150 grams (72%). By fractional distillation with a 4 ft. Podbielniak still column at 60/1 reflux ratio, the octadienes were found to contain 80%:2% of 2,6-octadiene (dicrotyl) and '-Z% 3-methyl- 1,5-heptadiene. No 3,4-dimethyl-1,5-hexadiene was found. The 2,6-octadiene thus obtained had the following properties: B. P. 125 0., ND 1.4312. (Henne, Chanan and Turk, J. A. C. S. 63, 3474 (1941) reported B. P. 124.5", ND 1.4336). The 3-methyl-1,5-heptadiene thus obtained was also identified by its physical properties, B. P. 112.5 0., ND 1.4240; (the previously reported values (Henne et a1.) were B. P. 111 0., ND

Example 3.3,6-dichloro-5-ethoxy-l-hexene was separated from its isomer by fractional distillation and had the following properties: B. P. 5060/0.3 mm., Nro 1.4622 (Pudovik, Izvest. Akad. Nauk. S. S. S. R. Otdel. Khim. Nauk 529- (1948) No. 5 Sept-Oct, gives B. P. 812/3 mm.. N13 1.4617). Seventy grams of this essentially pure isomer and 200 ml. methanol were treated slowly with stirring at 2530 C. with grams nickel carbonyl excess of the stoichiometric) After standing overnight the solution was diluted with water and the organic phase was separated with the aid of petroleum ether. The product was vacuum distilled from a few grams 'CaCOa, and the distillate, B. P., 45-172/1 mm., ,(largely 155-60/1 mm.), was fractionated to separate unreacted starting material. The latter was removed as a cut to 109/0.3 mm.; the remainder (45 grams, Np 1.4740) was subjected to infra-red absorption analysis. The spectrum was identical with that of the coupled product from 1,6-dichloro-5-ethoxy-2-hexene (Tabet, U. S. Patent No. 2,570,886), and showed a strong absorption band at 10.35 microns but no absorption band at 10.03 microns and only very weak absorption bands at 6.0 microns and 10.95 microns. These data show that the product was predominantly 1,12-dichloro-2,10diethoxy4,6- dodecadiene, i. e. that only very little branched chain product containing the -CH==CI-lz grouping was present.

Example 4.-3-chloro-3-methyl-1-butene was prepared by low temperature (-50 C.) addition of hydrogen chloride to isoprene and was separated from its isomer by fractional distillation (B. P. 38-41 C./190 mm., ND21 1.4189). Coupling of 222 grams of this isomer was carried out using 220 grams nickel carbonyl (20% excess) and 300 ml. methanol at ordinary temperature. The

product was mixed with CaCOs and was distilled. The distillate, 107 grams, was redistilled with a 4 ft. Podbielniak still column at 60/1 reflux ratio. Only two flats appeared: (1) B. P. 148-150", N9 14368-14405, 40 ml.; this appears to be (CH3)2C=CCH2C(CH3)2CH=CH2 (Henne and Chanan, J. A. C. S. 66, 392 (1944), give B. P. 149.7 C., N13 1.4391); (2) B. P. 162-164", N]: 1.4516-1.4556, ml; this evidently was another isomer, possibly although the refractive index was somewhat higher than the previously reported value for that particular isomer (l-lenne and Chanan give B. P. 168.6 C. ND20 1.4478.

It is significant that the rearrangements which occur in coupling non-terminal allylic halides by reaction with nickel carbonyl evidently are due, in part, to a specific influence of nickel carbonyl. Other coupling agents have been known to produce mixtures J. A. C. S. 67, 841 (1945)), which, evidently, do not contain predominantly the straight chain isomers.

The products obtained in the practice of this invention are valuable as intermediates for the manufacture of resin chemicals, etc. For example, the 1,10-dialkoxydecadienes obtained in the practice of this invention are especially valuable as intermediates for the manufacture of clibasic acids, since hydrogenation of these dialkoxydecadienes yields dialkoxydecanes which in turn can be converted to sebacic acid by oxidation.

I claim:

1. The process which comprises coupling terminal carbon atoms of an organic compound containing non-terminal allylic halogen by re action with nickel carbonyl, and separating from the resulting mixture the compound formed by the coupling of the said terminal carbon atoms.

2. The process of claim 1 in which the said reaction is carried out at a temperature of 50 to C.

3. The process of claim 1 in which the said halogen is chlorine.

4. The proces of claim 3 in which the said organic compound containing non-terminal allylic chlorine is 3- chloro-5-methoxypenten-1.

5. The process of claim 3 in which the said organic compound containing non-terminal allylic chlorine is 3-chloro-1-butene.

6. The process of claim 3 in which the said organic compound containing non-terminal allylic chlorine is 3-chloro-3-methyl-l-butene.

7. A process for preparing 1,10-dimethoxydecadiene-3,7 which comprises subjecting 3- chloro-5-methoxypenten-1 to the action of nickel carbonyl and thereafter separating 1,10-

dimethoxydecadiene-3,7 from the resulting reaction product.

8. A process for preparing 1,10-dimethoxydecadiene-3,7 which comprises subjecting 3- chloro-5-methoxypenten-1 to the action of nickel carbonyl at a temperature within the range of 0 C. to 150 C. and thereafter separating 1,10-

dimethoxydecadiene-SR from the resulting reaction product.

9. A process for preparing 1,10-dimethoxydecadiene-3,7 which comprises subjecting 3- chloro-5-methoxypenten-1 to the action of nickel carbonyl at a temperature within the range of 10 to 75 C. and thereafter separating 1,10-dimethoxydecadiene-3,7 from the resulting reaction product.

10. The process set forth in claim 9 in which the quantity of nickel carbonyl employed is at least 0.5 mols per mol of 3-chloro-5-methoxypenten-l.

11. The process of claim 9 in which the reaction is carried out in the presence of an inert organic diluent.

12. The process of claim 9 in which the reaction is carried out in the presence of methanol as an inert organic diluent.

IRVING D. WEBB.

References Cited in the file of this patent FOREIGN PATENTS Number Country Date 448,884 Belgium Feb. 1943 (Abstracted in Chemical Abstracts 41:6576 1947) OTHER REFERENCES Izvest. Akad. Nauk. S. S. S. R. Otdel. Khim. Naul. pages 321-9 (1948).

Abstracted in Chem. Abs., (1949). Article by Pudovik.

Wheland, Advanced Organic Chemistry, second edition, second printing, November 1949, pages 535-544. John Wiley and Sons, New York, N. Y.

vol. 43, page 130 

1. THE PROCESS WHICH COMPRISES COUPLING TERMINAL CARBON ATOMS OF AN ORGANIC COMPOUND CONTAINING NON-TERMINAL ALLYLIC HALOGEN BY REACTION WITH NICKEL CARBONYL, AND SEPARATING FROM THE RESULTING MIXTURE THE COMPOUND FORMED BY THE COUPLING OF THE SAID TERMINAL CARBON ATOMS. 